Version May 2024
INTRODUCTION — Torso hemorrhage represents the leading cause of potentially preventable death following traumatic injury [1-5]. A significant proportion of patients with torso hemorrhage can exsanguinate prior to definitive hemostasis due to the inability to apply direct pressure [6-9]. Internal hemorrhage requires rapid surgical intervention [10,11]. Aortic occlusion as a part of trauma management can decrease the volume of hemorrhage as efforts to resuscitate the patient and achieve definitive hemostasis continue. Options for aortic occlusion include direct clamping through an open incision (emergency thoracotomy or laparotomy) or inflation of an intra-aortic balloon using an endovascular approach [12,13]. (See "Overview of damage control surgery and resuscitation in patients sustaining severe injury".)
TORSO HEMORRHAGE — Noncompressible torso hemorrhage remains the leading cause of preventable death following military injury [2] and, from registry studies, significantly contributes to mortality in civilian traumatic injury as well [3-5]. Torso hemorrhage may originate from arterial, venous, or combined sources within the chest, abdomen, or pelvis. Management of hemorrhage generally consists of direct pressure to limit external bleeding during resuscitation and, subsequently, definitive repair to stop bleeding [14]. However, the inability to directly compress vessels in the torso leads to a significant proportion of patients exsanguinating prior to definitive management, often in the prehospital setting [6-9].
Traditionally, management of torso hemorrhage due to trauma has included direct aortic clamping via a thoracotomy for patients in extremis or an abdominal incision for those in the operating room. Several alternative management approaches to this vexing clinical problem have also been explored. Military antishock trousers (MAST) gained popularity many years ago as a noninvasive approach to prehospital torso hemorrhage control [15]. However, further evaluation of this approach demonstrated no clear benefit, and MAST use has since waned [16]. Another approach to torso hemorrhage is the use of intraperitoneal expanding foam that creates a tamponade effect to slow or stop bleeding [17,18]. This approach is not yet approved for use in the United States, although a phase III clinical trial is planned (REVIVE Trial, NCT02880163). Several external compression devices for noncompressible torso injury have been described [19].
RESUSCITATIVE AORTIC OCCLUSION — With developing expertise in endovascular therapies and the concurrent improvement in catheter technology, resuscitative endovascular balloon occlusion of the aorta (REBOA) is available to support perfusion of vital organs until definitive hemostasis can be achieved [12,20]. REBOA has the advantage of being less invasive than open thoracotomy and, in one small observational study, was associated with fewer early deaths and improved overall survival compared with resuscitative thoracotomy [21]. In a review conducted by the American Association for Surgery of Trauma (AAST) Aorta Study Group comparing 85 REBOA patients with 202 resuscitative thoracotomy patients, survival to discharge was higher with REBOA (10 versus 3 percent), particularly for patients not requiring cardiopulmonary resuscitation (22 versus 3 percent) [22]. Similarly, a systematic review reported a lower pooled mortality rate for REBOA compared with resuscitative thoracotomy (ie, open thoracotomy with aortic occlusion; five observational studies, adjusted OR 0.38, 95% CI 0.20-0.74) [23].
Evolution of endovascular aortic control — The earliest reported use of aortic balloon occlusion in trauma was during the Korean War, where a balloon catheter was inserted via the femoral artery into the thoracic aorta in two patients with abdominal bleeding [24]. Although neither patient survived deflation of the balloon, this report demonstrated the feasibility of balloon occlusion to aid resuscitation. Open aortic clamping in the operating room subsequently gained favor as a means to resuscitate patients in extremis. Some surgeons even advocated thoracic aortic clamping for patients with extrathoracic trauma who presented with tense hemoperitoneum and preserved pulses [25]. In subsequent years, resuscitative thoracotomy with aortic clamping, now typically performed in the emergency department, gained acceptance for the management of patients with traumatic arrest from torso injuries within a limited time window [26], and for some nontorso injuries [27]. (See "Resuscitative thoracotomy: Technique", section on 'Morbidity and mortality'.)
Balloon occlusion for traumatic arrest was again attempted years later, but results were similar to the initial experience during the Korean War due, in part, to equipment limitations [28,29]. These technical hurdles have largely been overcome with the maturation and proliferation of advanced endovascular techniques and improved catheter technology. In addition to serving as an adjunct to hemorrhage control in severe trauma, balloon occlusion techniques have been used successfully to manage bleeding associated with other pathologies such as pelvic bleeding from invasive placental conditions or postpartum hemorrhage [30-34], bleeding during elective orthopedic surgery [35-37], and control of hemorrhage from ruptured abdominal aortic aneurysm [38-43]. (See "Surgical and endovascular repair of ruptured abdominal aortic aneurysm", section on 'Aortic control and graft placement'.)
The military experience of the wars in Iraq and Afghanistan affirmed the need for improved methods of hemorrhage control [44,45]. One analysis of battlefield mortality demonstrated that one in four pre-hospital combat deaths and one in two in-hospital combat deaths were potentially preventable, with the overwhelming majority (91 and 80 percent, respectively) due to hemorrhage [46,47]. A sustained effort was made thereafter to characterize the physiology of aortic occlusion and to refine balloon occlusion techniques specifically for use during resuscitation for trauma. (See 'Physiology' below and 'REBOA technique' below.)
Physiology — In patients with hypovolemia, aortic occlusion (open or endovascular) can restore blood pressure to within normal physiological values (at least temporarily) by increasing cardiac afterload, thereby increasing cerebral and myocardial perfusion [48-50]. In a systematic review, a pooled analysis of six studies demonstrated an average rise in systolic blood pressure of 53 mmHg following balloon inflation [51]. Although both approaches effectively lower the volume of distribution of the remaining circulating blood volume, a minimally invasive approach may afford some benefit. In one animal study directly comparing REBOA with open, transthoracic aortic occlusion, the REBOA group required less resuscitation and vasopressor support and had significantly lower lactate levels than the open aortic occlusion group [48].
Large animal models of controlled [49,50,52-55] or uncontrolled hemorrhage [56-58] have further characterized the survival and metabolic implications of REBOA. Specifically, REBOA appears to be life-saving as compared with no occlusion in a model of severe liver injury with intraperitoneal hemorrhage (six of eight REBOA animals survived to the end of the five-hour observation period as compared with no survivors in the control group) [56]. However, progressively longer periods of balloon occlusion (up to 90 minutes) increase lactate levels, IL-6 levels, vasopressor use, and acute respiratory distress syndrome [49,50].
Importantly, although torso hemorrhage can originate from sites in the chest or from venous sources for which aortic control will have a more limited effect at reducing bleeding, REBOA may still have a role in these or any other clinical setting where a delay to definitive hemorrhage control is likely. Although expeditious definitive hemorrhage control must be the priority, REBOA can temporarily improve the patient's physiology (even though there may be some ongoing bleeding) by reducing the volume of distribution [57,59].
Aortic zones of occlusion — To facilitate the description of appropriate balloon placement, the descending aorta has been characterized as having three distinct zones [12].
●Zone I extends from the left subclavian artery to the celiac trunk, and occlusion in this region will control inflow to the abdominal viscera as well as to the pelvis and lower extremities (figure 1). Zone 1 REBOA should not be used if patients cannot proceed expeditiously to a definitive hemorrhage control procedure within 15 min [60].
●Zone II lies between the celiac trunk and the lowest renal artery and has traditionally been considered a zone of no occlusion, although the consequences of Zone II occlusion have not been specifically assessed [12]. With Zone II occlusion, there is also at least the theoretical risk of creating an intimal flap at the ostial opening of the visceral and/or renal vessels.
●Zone III is comprised of the infrarenal aorta, and occlusion in this region controls pelvic and lower extremity inflow (figure 2).
POTENTIAL INDICATIONS — Precise indications for resuscitative endovascular balloon occlusion (REBOA) in trauma remain open for debate [60]. Indeed, identifying patients who will truly benefit has proven difficult even for a well-defined single entity such as ruptured abdominal aortic aneurysm (AAA). (See 'Outcomes' below and "Surgical and endovascular repair of ruptured abdominal aortic aneurysm".)
In general, the presence of shock with an appropriate injury mechanism is an indication for REBOA. However, REBOA is best applied before cardiovascular collapse has occurred and may be more effective compared with waiting until the onset of pulseless electrical activity or a terminal arrythmia. The clinical parameters that define the ideal timing of REBOA application are difficult to know for certain, but some have attempted to determine an optimal blood pressure.
●One review suggested that REBOA should be considered in patients with abdominal or pelvic hemorrhage who have a detectable pulse but whose systolic blood pressure remains 80 mmHg or less following resuscitative efforts [61].
●Another study suggested a lower blood pressure of 60 mmHg, although even a threshold of 70 mmHg was associated with cardiovascular collapse [62].
●A consensus conference using the Delphi method, however, achieved consensus for using REBOA in patients with an initial blood pressure of <90 mmHg and no response to resuscitation [63].
REBOA can also be considered in those with traumatic cardiac arrest provided thoracic sources of hemorrhage or tension physiology have been excluded [64]. However, in such cases, establishing arterial access can prove difficult if not already established prior to full arrest. An alternative to waiting for traumatic arrest or profound shock to ensue is proactive arterial access in patients considered at high risk of torso bleeding [65,66]. In this manner, the femoral site can be used for blood pressure monitoring and serial blood gas chemistry analysis to aid with resuscitation and used for placement of a balloon catheter in more controlled circumstances should the need arise.
Abdominal trauma at risk for hemodynamic collapse — Patients with clinical signs of traumatic hemoperitoneum require expeditious hemorrhage control, which generally consists of damage control resuscitation and damage control laparotomy. However, for some patients, any reduction in cardiac afterload (such as with anesthesia induction agents causing vasodilation) can lead to circulatory arrest. Under this circumstance, a Zone I REBOA (figure 1) (see 'Aortic zones of occlusion' above) may offer a "physiological bridge." (See "Management of splenic injury in the adult trauma patient", section on 'Splenic embolization' and "Management of hepatic trauma in adults", section on 'Hepatic embolization'.)
Pelvic trauma at risk for hemodynamic collapse — For patients with pelvic trauma, Zone III REBOA (figure 2) can be used, provided the patient has no evidence of intra-abdominal bleeding. A more distal level of aortic occlusion has the advantage of maintaining visceral and renal perfusion, thereby reducing the degree of ischemia/reperfusion injury upon balloon deflation [50]. Specific algorithms for managing hemodynamically unstable patients with pelvic fractures have been well described [67-71]. In such patients, REBOA is well suited as a complimentary intervention to sustain proximal perfusion in patients who are transient responders or nonresponders to resuscitation [72].
Others — Aortic balloon occlusion for hemorrhage from compressible sites in the extremities has not been studied to date, although tourniquets for extremity hemorrhage have proven to be very effective. REBOA deployment prehospital or prior to transport to a referral trauma center has been reported [73-76]. However, such "extended" indications for REBOA should be carefully evaluated in the setting of a research protocol by teams facile with this technique [61]. The use of REBOA has also been reported in the management of nontraumatic life-threatening bleeding [77].
CONTRAINDICATIONS AND CAUTIONS — Patients who are not candidates for resuscitative thoracotomy should not be considered for resuscitative endovascular balloon occlusion (REBOA) [78]. REBOA has been used for great vessel injury to aid resuscitation in conjunction with open thoracotomy or sternotomy which are used to obtain proximal control [60]. (See "Resuscitative thoracotomy: Technique" and "Resuscitative thoracotomy: Technique", section on 'Contraindications'.)
Furthermore, patients with evidence of significant thoracic hemorrhage or pericardial tamponade should not undergo REBOA [60]. However, at least one preclinical study and a clinical series has suggested that thoracic trauma may not be an absolute contraindication for REBOA [79,80].
A relative contraindication to REBOA is inability to obtain femoral arterial access, which may be an issue for those patients who have undergone prior femoral vascular procedures or who have stigmata of severe peripheral vascular disease.
Personnel and facility requirements — REBOA is used primarily at high-volume trauma centers for patients with noncompressible torso trauma by clinicians experienced with the procedure [60].
Clinicians who perform the REBOA procedure can be drawn from diverse specialty backgrounds, but they should regularly undertake large-caliber vascular access procedures and be trained in REBOA placement [81,82]. Trauma surgeons, particularly those at high-volume trauma centers, should learn to gain arterial access and safely place aortic occlusion balloons. Moving beyond the control stage to any form of endovascular therapy should include the assistance of a vascular surgeon or interventional radiologist.
REBOA should not be placed if definitive surgical care and hemostasis is not available [60]. Interfacility transfer of patients with REBOA in place is also not recommended.
The team caring for the patient must also be prepared and capable of managing the complications associated with REBOA such as ischemia reperfusion injury, which can affect the abdominal organs, spinal cord, or lower extremities. (See 'Complications' below.)
PREPARATION
Devices and equipment — Available endovascular balloon catheters for aortic occlusion include both over-the-wire and wire-free options.
Over-the-wire balloons — Common examples of over-the-wire balloons include the Coda Balloon and the Q50. These balloon catheters require a large-caliber sheath (12 Fr or greater) to support placement and the use of a long wire (0.035" platform) and fluoroscopy to direct positioning of the wire and balloon, which can be cumbersome in an emergency setting, especially outside of the operating room [12].
Wire-free balloons — Wire-free, low-profile (7 Fr or 4 Fr) devices have been specifically developed and approved for emergency aortic occlusion and do not require use of radiologic equipment [83-87].
●The ER-REBOA device has a small nitinol wire inside of the catheter (referred to as a "wire in catheter hypotube" design) with enough stiffness to allow the device to be placed without the typically separate wire. This design enables the ER-REBOA catheter to be used more readily in emergency cases in which a long guidewire may not be available or practical, or for the provider who is less familiar with over-the-wire endovascular techniques.
●The next-generation ER-REBOA PLUS catheter has the same wire in catheter hypotube design as the ER-REBOA [88]. The ER-REBOA PLUS catheter does not need to be placed over a wire to provide hemostatic control, but the slightly larger and newly configured inner lumen will accommodate a 0.025" or smaller wire, if needed, to facilitate transition to a subsequent endovascular intervention. Such wire access could then be used to immediately transition to an endovascular procedure such as pelvic vascular, solid organ embolization, or placement of a covered endovascular stent.
●A 4 Fr aortic occlusion balloon (Control of Bleeding, Resuscitation, Arterial Occlusion System [COBRA-OS]) is also available for clinical use [87].
REBOA catheters with integrated pressure monitoring are meant to facilitate partial or intermittent REBOA (eg, partial-REBOA Pressure Regulated Occlusion [P-REBOA PRO]) [89-93]. The optimal conditions for using, and any benefit or harm to the "intermittent" or "partial REBOA" compared with complete occlusion, has not been established in the clinical environment [60]. A systematic review identified an increasing number clinical studies using partial REBOA [92]. In one study, survival was similar for partial and total occlusion, but the duration of partial occlusion was almost twice as long (median 58 versus 33 minutes) [94].
Timing of placement — The mean time to death following injury causing acute hemorrhage is one to two hours [5,10]. Thus, in patients with appropriate indications, prompt REBOA placement has the potential to save lives while delayed insertion or misplacement can introduce significant delays to the management of critical patients [65,73,74]. (see 'Potential indications' above and 'Outcomes' below).
Preemptive placement prior to hemodynamic collapse is ideal [62]. Balloon insertion can occur in the emergency department or in the operating room as long as balloon inflation time is minimized [95]. REBOA may also facilitate further imaging or access to angiography for embolization [96]. Alternatively, femoral arterial access can be obtained for monitoring alone if the need for REBOA is unclear but the patient demonstrates signs and symptoms of hemorrhagic shock. (See 'Potential indications' above.)
REBOA TECHNIQUE — There are five fundamental steps in the resuscitative endovascular balloon occlusion of the aorta (REBOA) procedure: arterial access and sheath placement, balloon catheter insertion, balloon inflation, balloon deflation after definitive hemostasis is achieved, and sheath removal [12,97-99]. Prior to initiating REBOA, the appropriate sterile equipment must be assembled (table 1). Prepacked kits should be available to facilitate placement in the emergent setting.
Obtain arterial access and place the sheath — The first step is to establish the access platform by which to deliver the aortic balloon catheter. Ultrasound-guided access is preferred is time permits and equipment is readily available [60,100] . (See "Percutaneous arterial access techniques for diagnostic or interventional procedures", section on 'Dynamic ultrasound guidance'.)
The common femoral artery (CFA) is used most commonly (figure 3) [51]. Transbrachial access has been described in one trauma case but may more often be applied to ruptured abdominal aortic aneurysm [39,101]. First, a sterile field must be created sufficient to permit operative access to the CFA and its branches, if it becomes necessary. One of three methods of arterial access can be used: percutaneous access with a needle (eg, 5-Fr micropuncture) and wire using a "Seldinger" technique, surgical cut-down, or a wire exchange through an existing arterial line. Ultrasound guidance for femoral access can be useful, if available. (See "Percutaneous arterial access techniques for diagnostic or interventional procedures", section on 'Common femoral artery'.)
Once a wire has been passed retrograde from the common femoral artery into the external iliac artery, an access sheath (30- to 45-cm sheath for over-the-wire or 10- to 15-cm for wire-free) can be advanced. It is important to use a sheath size that will accommodate the balloon catheter planned for use and also to advance any wires or sheaths with caution, stopping if resistance is encountered. Once a sheath has been inserted successfully and secured into place, the wire and tapered introducer can be removed (picture 1). It is good practice at this stage to withdraw blood from the sheath and flush it with 0.9% saline with heparin (10 Units heparin/mL saline).
Insert the balloon catheter — If a wire-free balloon catheter is available (eg, ER-REBOA catheter), this can be advanced into the sheath, taking care to keep the centering "P-tip" of the catheter unfurled using the peel away sheath. For an over-the-wire balloon catheter, a long "working" wire (eg, Rosen, intermediate stiffness) can then be inserted through the sheath and advanced into the aorta. A two-step wire exchange is preferred by some to place a stiffer wire (eg, start with a J wire and upgrade to an Amplatz).
For over-the-wire insertion, fluoroscopic guidance or serial digital radiographs should be used to ensure the wire remains within the thoracic aorta and has not deviated into a visceral branch or the aortic arch. Although experience is limited for this indication, another option is to use transabdominal ultrasound (if available) to identify and position the wire [100,102-104]. A subxiphoid view, such as that obtained during focused assessment with sonography for trauma (FAST), is thought to be optimal, since the imaging window through the left lobe of the liver includes a view of the thoracic aorta. This technique enables confirmation of central aortic wire position; however, the technique has only been described during elective endovascular procedures and has not been validated in the emergency department setting. If none of these is available, the experienced interventionalist can use external landmarks and catheter markings. In a systematic review, "fluoroscopy-free" (landmark only, landmark plus ultrasound or radiographic confirmation) deployment was reported to have a low rate of serious complications [51]. The wire-free ER-REBOA catheter is also approved for fluoroscopy-free placement. Computed tomographic measurements have also been used to determine safe insertion depths for both Zone I and Zone III placement [105-107]. A cadaver-based study concluded that the use of midsternum external landmark technique had a nearly 100 percent likelihood of successful Zone I deployment (figure 1) [108]. Whether computed tomography (CT)-based measurements are more reliable for balloon placement compared with external landmark or ultrasound-based landmarks requires prospective evaluation.
Inflate the balloon catheter — A 10- to 20-mL Luer lock syringe should be filled with a dilute mix of 0.9% saline and iodine-based contrast solution. This should be attached to the balloon port, and the balloon should then be inflated slowly to avoid over-inflation and balloon rupture (image 1). For over-the-wire catheters, it is important to maintain the long sheath in place just below the balloon to provide support and prevent the balloon from being pushed inferiorly as it inflates. As the balloon adopts the contour of the aorta and resistance is felt in the syringe, inflation is complete. For over-the-wire catheters, the wire should be left in place to stiffen the catheter shaft and avoid balloon migration.
A clinical method of confirming aortic, rather than iliac, artery placement is to palpate for the contralateral femoral pulse, which should be absent. Additionally, an absent left brachial pulse should alert the operator to a distal arch placement, proximal to the left subclavian artery.
An ultrasound technique for balloon positioning has also been described for infrarenal occlusion. Insufflation of the balloon with a solution containing a microbubble contrast agent enhances ultrasound observability [103]. Again, human data in an emergency setting are lacking, and such techniques should be considered experimental.
Identify and control bleeding — Upon inflation, the balloon catheter (and wire, if applicable) should be secured to the patient's leg in such a way that prevents balloon migration. The inflating syringe should remain attached to the balloon port with the stopcock in the off position. The next step in management should be determined by the attending trauma surgeon. In all cases, damage control resuscitation should continue. Typically, patients will be taken for emergency operative or endovascular control of hemorrhage if they are not already in the operating room. Although obtaining a CT of the head and/or torso with the balloon in place has been described, this risks prolonged ischemic time and delays definitive hemorrhage control [109]. (See "Overview of damage control surgery and resuscitation in patients sustaining severe injury".)
Duration of inflation and balloon deflation — The duration of Zone I REBOA should be minimized, with one guideline suggesting limiting the duration of balloon occlusion to 15 minutes and underscoring the need for expeditious transfer to the operating room for definitive hemorrhage control [60]. Zone III REBOA may be tolerated for a longer period, but the safe duration of occlusion is unknown. A target occlusion time less than 30 minutes and no longer than 60 minutes is suggested [60].
Deflation of the REBOA balloon requires close communication with the anesthesia team [110]. Ideally, definitive hemostasis will have been achieved, along with sufficient resuscitation to generate normal hemodynamic indices. Slow, incremental deflation should then be performed, recognizing that even the smallest reduction in balloon volume results in significant blood flow beyond the site of occlusion [89].
On occasion, it may be clinically necessary to deflate the balloon partially, either to identify a bleeding focus or to permit transient reperfusion between occlusion periods. If this is required, the anesthesia team should be ready to volume load the patient and add vasoactive medications as needed to avoid a precipitous cardiovascular collapse following balloon deflation. Furthermore, once the balloon is fully deflated, it is prudent to leave the catheter in place until the surgical or endovascular maneuvers are completed in case emergent reinflation is required.
Remove the balloon catheter and sheath — Once the balloon catheter and sheath are no longer required, they should be removed. The balloon catheter can be removed from the sheath without any special consideration, but sheath removal requires management of the arteriotomy. This can be accomplished by one of three methods: operative exposure and direct repair, the use of a closure device, or direct pressure for sheath sizes of 7 Fr or less. (See "Percutaneous arterial access techniques for diagnostic or interventional procedures", section on 'Hemostasis at the access site'.)
The limb should be monitored for at least 24 hours following sheath removal.
OUTCOMES — Outcomes for REBOA have been evaluated mostly at large trauma centers and consists of observational data primarily from retrospective reviews [22,23,51,69,96,101,109,111-119]. Overall, utilization of REBOA has increased overall and appears to be associated with reduced mortality [120].
While survival may be improved for some patients, identifying which patients remains difficult. In many cases, REBOA may not substantially alter the outcome, either because the patient's injuries could be handled with conventional techniques or because their injuries are devastating. In one review using data from the Trauma Quality Improvement Project (TQIP) database, mortality was higher among severely injured patients who underwent REBOA compared with a propensity-matched cohort who did not (no REBOA or resuscitative thoracotomy) (36 versus 19 percent) [121,122]. (See 'Potential indications' above.)
Zone I — In the largest study evaluating outcomes for Zone I REBOA (figure 1), 452 patients with a mean injury severity score of 36 were compared with a matched non-REBOA cohort using the Japanese Trauma Databank [123]. The overall mortality rate was 76 percent. Survival was significantly decreased for those who underwent REBOA compared with those who did not (odds ratio 0.30, 95% CI 0.23-0.40). A later review from the AORTA registry from 2013 to 2021 compared zone I REBOA with resuscitative thoracotomy (RT) [111]. Among 56 pairs of comparable patients, zone I REBOA was associated with a significantly lower mortality compared with RT (78.6 versus 92.9 percent). In multivariate analysis, the survival benefit of zone I REBOA remained after adjustment for significant confounders (relative risk [RR], 1.25; 95% CI, 1.15-1.36). In another study of patients with extrathoracic bleeding, 24 patients who underwent REBOA were compared with 72 patients who underwent resuscitative thoracotomy [21]. The groups were well matched for injury characteristics. The mortality rate was significantly lower for the REBOA group compared with resuscitative thoracotomy (9.7 versus 37.5 percent). Each arterial access site was repaired with open surgery, and there were no reported access site complications. Outcomes may be related to the volume and frequency of REBOA, given that more favorable outcomes have been reported in studies from high-volume centers in Japan and the United States than were reported in a 16 center trial in the United Kingdom that included 13 low-volume centers, which is reviewed below [124]. (See 'Zone III' below.)
In one report from two Level 1 trauma centers in the United States, four patients with hemorrhagic shock were treated with using Zone I REBOA [109]. Each patient also required operative hemorrhage control with one nonhemorrhagic death due to traumatic brain injury. Three other series from Japan report on a total of 45 patients [96,117,118]. One of these presented seven patients with solid organ and pelvic injury, each of whom was managed nonoperatively using endovascular techniques [96]. REBOA was used during the initial resuscitation to stabilize patients, with one reported fatality. Another series described 14 patients with a mixture of abdominal injury patterns [117]. There were nine fatalities, with survivors requiring significantly shorter occlusion times (46 versus 224 minutes). A series of 24 severely injured patients with a predicted survival of 12.5 percent where REBOA was used achieved an actual survival of 29.2 percent, representing a major gain in survival [118]. That group also reported three vascular complications resulting in lower extremity amputation.
Zone III — Zone III deployment to manage hemorrhage associated with blunt pelvic fracture has increased. In a review of the AORTA registry, zone III deployment increased significantly over a five-year period (2014 to 2018) from 14.7 to 40.6 percent and was associated with decreased mortality (adjusted odds ratio 0.33, 95% CI 0.20-0.55) [120].
Retrospective reviews and case series of patients with isolated pelvic fractures have supported Zone III occlusion (figure 2) [69,109]. In an early series of 13 patients, the injury burden was high with a mean Injury Severity Score (ISS) of 48±16 and a mean systolic blood pressure (SBP) of 41±26 mmHg [69]. The predicted survival was 39 percent but the actual survival of 46 percent. All fatalities were from hemorrhagic shock with four deaths due to a failure of hemorrhage control and three due to multiorgan failure. Another report included two patients injured by a blunt mechanism who presented with an SBP of 70 and 85 mmHg [109]. Following Zone III REBOA, the SBP rose to 135 and 125 mmHg respectively. Both patients went on to definitive hemostasis (pelvic angioembolization), but one of the patients eventually died from a traumatic brain injury.
A review of the American College of Surgeons Trauma Quality Improvement Program database (ACS-TQIP) included 156 matched patients with blunt pelvic fractures who underwent REBOA alone, preperitoneal pelvic packing (PPP), or both [125]. REBOA alone compared with PPP or REBOA + PPP was associated with the lowest 24-hour mortality (14 versus 25, and 35 percent, respectively) and in-hospital mortality (29 versus 44 and 54 percent, respectively), fewer packed red blood cells transfused, and faster times to laparotomy and/or angioembolization. An earlier ACS-TQIP review had favored PPP [126]. Studies of the AAST Aortic Occlusion for Resuscitation in Trauma Acute Care Surgery (AORTA) Registry similarly demonstrated favorable outcomes for REBOA use in pelvic fractures [127,128]. In one of these reviews, zone III deployment was associated with significantly decreased mortality [120].
Not all studies have reported uniformly favorable results for REBOA. A multicenter trial from the United Kingdom randomly assigned patients with confirmed or suspected exsanguinating torso hemorrhage to a strategy that included REBOA and standard care (46 patients) or standard care alone (44 patients) [124]. The median Injury Severity Score was 41. Fourteen patients (30 percent) in the REBOA group had a definitive hemorrhage control procedure compared with 19 patients (43 percent) in the standard care alone group. Definitive surgery included abdominal (n= 28), pelvic (n=5), and extremity revascularization procedures (n=5); one patient underwent thoracotomy. Within the REBOA group, only 19 of the 89 patients allocated to the REBOA arm progressed to balloon inflation. Failure to obtain vascular access was high in this study at 22 percent. Overall, more deaths due to bleeding occurred in the REBOA group compared with the standard care alone group (8 of 25 patients [32 percent] versus 3 of 18 patients [17 percent]), with most occurring within 24 hours. Within the REBOA group, those patients who failed standard of care and progressed to balloon inflation experienced better survival compared with those patients who did not improve with standard therapies and did not receive REBOA due to failure of vascular access (50 versus 30 percent survival). All-cause mortality was overall increased for the REBOA group but was not significantly different at 90 days (54 percent versus 42 percent; odds ratio 1.58, 95% credible interval 0.72-3.52). The median time from randomization to definitive hemorrhage control was 19 minutes longer in the REBOA group (average time from injury to surgical control was 183 minutes). Transfusion requirements were similar between the groups.
COMPLICATIONS — Reported complications from REBOA include arterial injury at the access site or the aorta, thromboembolic complications from the balloon and/or sheath, and end-organ failure [97,129-133]. The pooled rate of vascular access complications was 8.6 in a systematic review that included 713 patients [130]. In a comprehensive report on REBOA complications from the American Association for Surgery of Trauma (AAST) AORTA registry, complications were overall uncommon and included groin complications (eg, pseudoaneurysm) in 5.6 percent [133]. Lower limb amputation was required in 2.1 percent of patients, of which three cases (0.7 percent) were directly related to the vascular puncture from the REBOA insertion. In a smaller review, embolism occurred in 4.3 percent, and there were no limb ischemia events.
FUTURE DIRECTIONS — Future efforts in REBOA application include the conduct of randomized controlled studies to better inform clinical care and improvements in balloon technology to limit distal ischemia and complications.
Advances in balloon and catheter technology for next-generation REBOA should include attributes that simplify and enhance the safety and therapeutic benefit of REBOA. Preclinical studies evaluating improved REBOA catheters and techniques are ongoing [89,90]. Future efforts should seek to expand the endovascular devices and methodology specifically for use in trauma. (See "Surgical and endovascular repair of blunt thoracic aortic injury", section on 'Endografts and sizing'.)
As with the transition from open to endovascular repair for many vascular pathologies, trauma and acute care surgeons need to acquire the necessary catheter skills, either through special skills training or ideally as a part of residency or fellowship training [81,134-136].
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: General issues of trauma management in adults" and "Society guideline links: Thoracic trauma".)
SUMMARY AND RECOMMENDATIONS
●Torso hemorrhage and resuscitative aortic occlusion – Noncompressible torso hemorrhage is a leading cause of trauma mortality. Aortic occlusion as a part of trauma management can decrease the amount of bleeding distal to the occluded aortic site to provide a window of opportunity for resuscitation and definitive hemorrhage control. Options include direct clamping through an open incisional technique and resuscitative endovascular balloon occlusion (REBOA). REBOA is a hemorrhage control and resuscitation adjunct that has the advantage of being less invasive than open thoracotomy, and preemptive placement prior to hemodynamic collapse is possible. (See 'Torso hemorrhage' above and 'Resuscitative aortic occlusion' above.)
●Potential indications – Precise indications for REBOA in trauma remain poorly defined, but patients who are not candidates for resuscitative thoracotomy should not be considered for REBOA. Further, REBOA does not replace resuscitative thoracotomy in patients with circulatory arrest after penetrating chest trauma. REBOA can be considered for patients with abdominal or pelvic hemorrhage who have a detectable pulse but whose systolic blood pressure remains 80 mmHg or less. Thoracic aortic occlusion (Zone I) (figure 1) should be considered in exsanguinating abdominal injury. Infrarenal aortic occlusion (Zone III) (figure 2) should be considered in hypotensive patients with severe pelvic fractures. For patients with torso trauma at risk for hemorrhagic shock, access for REBOA can be obtained preemptively in the emergency department or in the operating room and used for placement of the balloon catheter should the need arise. (See 'Potential indications' above and 'Aortic zones of occlusion' above.)
●REBOA technique – The REBOA catheter is placed and positioned in a stepwise manner using fundamental endovascular techniques. The essential steps for use of a REBOA include arterial access and sheath placement (typically common femoral artery), balloon catheter insertion, balloon inflation, definitive operative hemorrhage control, balloon deflation, and sheath removal. (See 'REBOA technique' above.)
●Outcomes and complications – Compared with no occlusion, REBOA is associated with significantly reduced mortality, but mortality rates are increased with prolonged occlusion times. Reported complications from REBOA include arterial injury at the access site or the aorta, thromboembolic complications from the balloon and/or sheath resulting in limb ischemia, and end-organ failure. (See 'Outcomes' above and 'Complications' above.)
●Future directions – Further study is needed to determine the ideal timing of REBOA placement, the tolerable duration of balloon inflation, and the full spectrum of eligible patients who may benefit from this innovative resuscitative procedure. (See 'Future directions' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Jonathan Morrison, MD, PhD, FRCS, who contributed to an earlier version of this topic review.
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